Page 1 of 2 12 LastLast
Results 1 to 13 of 23
  1. #1
    Join Date
    Jan 2007
    Posts
    735

    Exisiting 18/2 network vs LON

    Does anyone know what happens if you try and use an existing 18/2 network with new Lonworks controllers?

    Assume the old proprietary controllers are gone.

  2. #2
    Join Date
    Feb 2005
    Posts
    345
    LON's pretty tough, if the existing cabling is in good shape (ohm it out) and you're not getting paid to install a new string, it'll probably work fine.

    Make sure the existing wire's not run near noise generators, and if it's a large network, you may want to break it down into several segments (via routers) to contain any unfriendliness. If it's a multi-floor facility, consider running a new backbone and using the existing wire for subnets only. You may also want to have a couple of physical layer repeaters in your bag of tricks to ram information through if things get bad, and I'd plan on doing your best to design/implement as a double terminated buss architecture, with the last node on a subnet being close to the first node and close to the backbone. That way, if there are problems, you can trace down the offending segment for repair/replacement easily, and if things are too noisy, you can run single segment from the last node to the router (or first node) to form a loop (on that subnet).

    More than likely you'll end up with a network that's noisier than you'd like, but functions properly.

    Nikko

  3. #3
    Join Date
    Jan 2007
    Posts
    735
    Two AHU's, two boilers, one large Trane Box Car, all in very close to each other on the roof.

    Then a chiller out in the parking lot (Chilled water needed for accuracy, but roof couldn't take the weight).

  4. #4
    Join Date
    Feb 2005
    Posts
    345
    I'd try it - but that's me

    Nikko

  5. #5
    Join Date
    Sep 2002
    Location
    Hampton Roads, Virginia
    Posts
    1,594
    I have a small Lon network that has one controller approx 500 feet away from the rest of the network, that is connected by 2pr telephone cable, it was available and works without any problem.

    Kevin
    "Profit is not the legitimate purpose of business. The legitimate purpose of business is to provide a product or service that people need and do it so well that it's profitable."

    James Rouse

  6. #6
    Join Date
    Feb 2005
    Posts
    345
    I did the same thing (1 pair of phone wires), but I was a little over a full city block away and up 15 floors for one controller . That network segment was noisier than hell (I isolated it with it's own router to keep the crud off the rest of the network), but it worked!

    Nikko

  7. #7
    Join Date
    May 2002
    Posts
    9,564
    I had a wicked site that I was told to reuse 18/2 wires in a star configuration for about 20 rooftop units... and it worked. Runs were anywhere from 20-200 feet. But, really, you need to figure out how to do it properly if you can...

  8. #8
    Join Date
    Mar 2005
    Location
    Pacific Time Zone
    Posts
    4,195
    I do! I do! What a PIA it was, but a great learning experience.

    Powers System 600 system with 18/2 comm wire. Some tinned, some not, some shielded, some not. Ran 22 ga Echelon rated wire between new controllers, basically all the I/O's for the central plant, like 10-15 and then a bunch of asc's. About 45 controllers total. I never did quite understand the reasoning behind the original topology, but anyway everything worked fine until around the 35th controller. Different devices would go offline, put in terminators not as recommended, but at the device going offline the most and it helped the issue. System was a free topology system overall, but it had a partial bus, star and something else. From memory there were technically 3 networks all coming back to a main panel/SCU. Anyway tied them all together and everything would actually talk, but one controller. Yeah intermittent communication problems, but for the most part things worked fine, except for the one controller and if I had to download to a programmable controller it was 50/50 if I would have to have some one go to site and cycle power/reset the controller as the download would hang due to the communication issues. Anyway I ended up purchasing a L-Switch not sure of the model but it has 4 FT-10 ports and 1 1250 port. (Sysint - you can pass some commission my way ) I ended up putting the L-Switch in and used all 4 FT-10 ports and leaving it configured for auto learning. Did not even put it on my Lonmaker drawing. I tried to put all most like wire types on each port, ie 18/2 tinned on one port, 18/2 shielded one another, 18/2 non-tinned on another and the last port I put all my 22/2 Echelon rated comm line on and terminated each port/channel according to its topology. This cleaned everything up and I could then and still can reliably talk to and download to everything. Granted the L-Switch was not cheap, but it was still cheaper than running new wire, but with my commission fee tacked on... Anyway best of luck.
    "How it can be considered "Open" is beyond me. Calling it "voyeur-ed" would be more accurate." pka LeroyMac, SkyIsBlue, fka Freddy-B, Mongo, IndyBlue
    BIG Government = More Dependents
    "Any 'standard' would be great if it didn't get bastardised by corporate self interest." MatrixTransform
    http://threedevilskennel.com/ - not my website.
    Versatile Hunting Dog Federation - www.vhdf.org/


  9. #9
    Join Date
    May 2002
    Posts
    9,564
    Thanks!

    Lets face it. The L-switch is extremely convenient to solve issues like this.

    When you think about it, planning your architecture around some connectivity products is a good idea. Too many guys haven't sat done and put together a simple sheet telling them what they are buying for networking. This seems to be the biggest mistake I'm encountering. This is very surprising to me.

  10. #10
    Join Date
    Mar 2008
    Posts
    86
    I have changed over 10-15 schools taking out Andover. In every school I installed a Jace, and I reused the 18/2 shielded trunk in every one of them. I feel that the length of my trunk was shortened as in several of them I had to install repeater, especially if the trunk was starred. The cost of a repeater is nothing compared to re-pulling the trunk. I have never tried it without a Jace. With a Jace the trunk worked fine

  11. #11
    Join Date
    May 2002
    Posts
    9,564
    That would have been a great spot for a smart switch rather than a repeater.

  12. #12
    Join Date
    Mar 2008
    Posts
    86
    Never used a smart switch. Got a link? Like to see the difference.

  13. #13
    Join Date
    Jul 2008
    Posts
    22

    Re: Lon cabling

    Quote Originally Posted by simsd View Post
    Does anyone know what happens if you try and use an existing 18/2 network with new Lonworks controllers?

    Assume the old proprietary controllers are gone.
    I was on a job where the install guys pulled 18/2 shielded underground throughout a high school campus. We did'nt want to repull and did'nt want to find out what would happen if we just 'tried' it. Ended up finding a white paper from the manufacturer telling me to ground the shield in series with a capacitor and a resistor on one end of each segment. Sorry, cant remember values. But it worked. This essentially converted the 18/2 shielded to a lon trunk.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event